The research entails anatomical, biochemical, and ablation-behavior analyses of neocortex in primitive mammals. The long term objective is to discover the contribution of sensory, association, and motor cortex to the neurological and psychological adjustment of man to his environment. The specific aims include the assessment of the structure and function of major areas of neocortex in a number of primitive mammals, including opossum, mouse opossums, armadillos, hedgehogs, tree shrews, and bushbabies, specifically selected to allow inferences to the extinct animals in mankind's ancestral lineage. The methods include anatomical tract-tracing techniques to determine the changes in the location, extent, and connections of sensory and motor areas, receptor-binding techniques to determine changes in the biochemical characteristics of the same areas, and ablation techniques combined with rigorous behavioral testing to determine the changes in the contributions of these areas. In this manner the evolutionary development of Primate neocortex is traced from its most primitive mammalian form to its current form in an attempt to understand the contributions of its many parts. Since surgical ablation duplicates the type of brain damage that often results from stroke, the inquiry also can be expected to yield information about the fragmentation of man's psychological capacities as a result of cerebrovascular accidents.